1. Field of the Invention
The invention relates to a method and system for retrieving lost or stolen devices. More particularly, the invention relates to a method and system for identifying lost or stolen portable computers as they pass through an airport checkpoint.
2. Description of the Related Art
The theft of portable devices, especially portable electronic devices, continues to be a widespread problem in the United States and world-wide. Each year, millions of dollars worth of electronic equipment such as portable, or laptop, computers are stolen or lost. Typically, when a device is lost or stolen, the owner has no way of retrieving or otherwise locating the device. He or she is then forced to replace the lost item, or make do without it.
Currently existing technology allows devices to be identified by means of radio frequency identification (RFID) tags. RFID technology uses electromagnetic energy (such as radio) as a medium through which information is sent. Referring to FIG. 1, an RFID system 100 is illustrated. The RFID system 100 includes an RFID tag 102 for transmitting and/or receiving radio frequency signals and a reader 104 for receiving radio frequency signals from the RFID tag 102 and transmitting radio frequency signals to the RFID tag 102. The system 100 also includes a computer 106 which is coupled to the reader 104 by a communications link 108. The communications link 108 may be any one of various types of well-known communication links such as a cable line that directly connects the reader 104 to the computer 106, an Ethernet communications link, or a modem communications link, for example. Through the communications link 108, the reader 104 can receive commands and data from the computer 106 and, thereafter, send data to the remote RFID tag 102. As was noted above, the reader 104 can also receive data from the remote RFID tag 102 and pass the data back to the computer 102.
RFID technology overcomes many limitations of other automatic identification approaches, such as those using bar codes and infrared technology, which use light to communicate. Since an RFID tag 102 does not require a visual scanner, or other vision system, to detect its presence, it may be hidden or invisible to the eye and may also be used in harsh or dirty environments. A reader 104 reads information transmitted by the RFID tag 102 even if the tag 102 is completely hidden from view.
An RFID tag 102 typically includes a receiver and some type of transmitter, an antenna, and memory. There are two categories of RFID tags—active and passive—that represent two different types of RF communication. Tags without batteries are known as passive tags because they derive their power from the RF energy transmitted from a reader. Passive RFID tags tend to be smaller and exhibit short range transmission characteristics (under six feet), whereas battery-powered, active tags, tend to be larger and exhibit long range transmission characteristics (over one hundred feet).
Active tags send data back to the reader with radio power generated from a battery within the tag. Passive tags, on the other hand, use modulated backscatter (MBS) to transmit reflected energy, dictated by the data stream from the tag, back to the reader. Passive tags using MBS are better suited for gate or lane applications where it is undesirable to wake up (see) any tags beyond a certain distance and where there are few obstructions in the energy path.
With the aid of RFID technology, devices which are brought within range of a reader, or interrogator, may be detected. Furthermore, known devices, such as those on assembly lines, can be identified and their progress tracked using this technology. However, there is currently no method or system which provides a mechanism by which it can be determined if the device being detected is lost or stolen. To accomplish this purpose and to be of value, such a system would not only have to identify the device, but be able to determine that it was, in fact, lost or stolen and thereafter, notify appropriate personnel of the matter. Additionally, the reader of such an anti-theft/retrieval system, would best be strategically located so as to make it likely that a significant number of lost or stolen devices would come within range of the reader.
Therefore, what is needed is a method and system of identifying devices, which are randomly brought within range of a reader, determining if the detected devices are lost or stolen and thereafter, notifying appropriate security personnel when such device is located.